Fume-exhaust hood for electric furnace

ABSTRACT

An insulated supporting framework including a circular refractory lined water-cooled ring around the furnace electrodes stands on the roof ring of the furnace. A stainless steel hood including a cylindrical sidewall with damper control and a refractory lined water-cooled cover with electrode holes therein is carried by the insulated frame, fitting within the ring thereof. A stainless-steel refractory-lined exhaust outlet extends radially from the sidewall and damper-controlled inlet extensions from the hood and outlet project over the rear and side doors of the furnace. Radial bearing lugs on the hood engage the insulated frame between adjustable positioning screws.

United States Patent lnventor Bernard J. Lucas Duquesne, Pa. Appl. No. 825,202 Filed May 16, 1969 Patented Jan 12, 1971 Assignee United States Steel Corporation a corporation of Delaware FUME-EXHAUST HOOD FOR ELECTRIC FURNACE 1 Claim, 5 Drawing Figs.

U.S. Cl 13/1, 98/1 15 Int. Cl B08b 15/02; F 27d 17/00 Field ofSearch l3/1,9, 31; 98/1 15 Primary ExaminerBernard A. Gilheany Assistant Examiner Roy N. Envall, Jr. Att0rneyDonald S. Ferito ABSTRACT: An insulated supporting framework including a circular refractory lined water-cooled ring around the furnace electrodes stands on the roof ring of the furnace. A stainless steel hood including a cylindrical sidewall with damper control and a refractory lined water-cooled cover with electrode holes therein is carried by the insulated frame, fitting within the ring thereof. A stainless-steel refractory-lined exhaust outlet extends radially from the sidewall and damper-controlled inlet extensions from the hood and outlet project over the rear and side doors of the furnace. Radial bearing lugs on the hood engage the insulated frame between adjustable positioning screws.

.P NIED JAN-1 219m 3555163 sum 3 OF 3 nv vew ran.

BERNARD .1. LUCAS FUME-EXIIAUST HOOD FOR ELECTRIC FURNACE This invention relatesto an exhaust hood for an electric furnace and, more particularly, to a hood removably disposed in an insulated structural frame standing on the furnace roof.

BACKGROUND OF THE INVENTION The fumes evolved in an electric furnace, particularly when oxygen is being used therein, have long been a troublesome source of air pollution and numerous attempts have been made to remedy it. The latter have not been wholly successful, however, so far as I am aware, and leaveconsiderable room for improvement. The most pertinent prior art known to me comprises U.S. Pat. Nos. 2,932,679 and 2,935,927.

The object of my invention is to provide a compact, insulated, adjustable hood fitting the furnace electrodes rather closely and adapted to collect fumes arising directly from the melt as well as leakage which may occur through the furnace doors.

SUMMARY OF THE INVENTION In a preferred embodiment, I construct a rectangular insulated frame adapted to stand on the furnace roof and mount therein a ring capable of removably supporting a stainlesssteel, refractory lined, damper-controlled cylindrical hood extending downwardly to a level closely adjacent the furnace roof with adjustable stainless-steel skirt plates. The hood has a cover thereon provided with holes to receive the furnace electrodes. An exhaust outlet extends radially from the sidewall of the hood. Auxiliary damper-controlled inlets project from the hood and outlet over the rear and side doors of the furnace. The entire hood is carried on the insulated frame by radial bearing lugs which engage the insulated frame ring between adjustable positioning screws.

BRIEF DESCRIPTION OF THE DRAWINGS A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating the present preferred embodiment.

In the drawings:

FIG. 1 is a plan view showing my improved hood in position on a furnace;

FIG. 2 is a side elevation thereof; 7

FIG. 3 is a vertical section taken along the plane of line Ill-III of FIG. 1;

FIG. 3a is a portion of FIG. 3 to enlarged scale and with parts omitted; and

FIG. 4 is a plan view of the hood-supporting frame.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in detail to the drawings, the main supporting frame 10 (FIGS. I and 4) of my invention comprises spaced parallel longitudinal rails 11 connected by cross members 12 and 13. Legs 14 at the ends of rails 11 stand on the roof ring 15 of a furnace 16. An auxiliary support 17 for an exhaust outlet extends from one side of frame 10 and a wall 21 is hung from frame 10 on angle brackets 19. Segmental skirt plates 20 are adjustably secured at the lower edge of said cylindrical wall 21 to close the gap between wall 21 and furnace roof 22. Covers 23 are removably disposed on a ring 18 which is tubular as are radial ribs 25, connected therewith, for circulation of coolant. Ring 18 is adjustably mounted on top of wall 21. Wall 21 and covers 23 form a turret and are lined with refractory material for heat protection-The covers have electrode holes therein.

Members 11 and 12 of frame 10 have a pair of spaced blocks 26 at the midpoints thereof, each of which has a screw 27 adjustably extending therethrough. The screws of the blocks of each pair together provide a gap to receive one of four positioning lugs 28 projecting radially from ring 24. Covers 23 may be lifted from frame 10 after electrode withdrawal.

As shown in FIG. 3, outlet 29, supported on extension 17,

communicates with the space inside wall 21, and with a downcomer 30, connected to a suction fan and filter bags (not shown). Inlet extensions 31 and 32 project from wall 21 over the rear and side doors of the furnace, respectively, to collect any fumes leaking therefrom.

Furnace-roof coolers 33, normally positioned as shown in FIG. 3, are connected by chains 34 to points of anchorage 35 on frame 10. The coolers are thus lifted when frame 10 is removed after electrode withdrawal. Lifting eyes 36 on frame 10 are adapted to receive crane hooks.

It is clear that my improved hood has numerous advantages. It makes a close fit with the furnace roof and electrodes so that inward leakage of air is minimized and yet provides for collecting fumes leaking from the doors. The construction is simple and normal operation may be effected without difficulty.

I claim:

1. An exhaust hood for an electric furnace comprising a frame adapted to stand on the roof of the furnace, a supporting ring positioned in said frame, a turret having an exhaust outlet disposed on said ring, the lower edge of the turret closely approaching the roof of the furnace, and segmental skirt plates adjustably secured to the lower edge of the turret. 

1. An exhaust hood for an electric furnace comprising a frame adapted to stand on the roof of the furnace, a supporting ring positioned in said frame, a turret having an exhaust outlet disposed on said ring, the lower edge of the turret closely approaching the roof of the furnace, and segmental skirt plates adjustably secured to the lower edge of the turret. 